1. Field of the Invention
The present invention relates generally to a method of attaching a solid state imaging device, and more particularly to a method of attaching a solid state imaging device, which reduces the thickness required for the attachment and realizes the accurate attachment of the solid state imaging device.
2. Description of Related Art
In a conventional method of attaching a solid state imaging device to an optical unit, a package 2 loaded with a solid state imaging device chip 1 is mounted on a CCD substrate (not illustrated) through an aluminum board 3 as shown in FIG. 11. An optical low-pass filter 5, a rubber member 6 and the package 2 are sequentially inserted into the optical unit 4 from behind. The aluminum board 3 is fixed to the optical unit 4 by screws 7 or adhesives. Incidentally, the package 2 may be directly mounted on the CCD substrate with a predetermined strength without providing the aluminum board 3, and the CCD substrate may be fixed to the optical unit 4.
If the package 2 is attached to the optical unit 4 as stated above, however, the positional accuracy of a light receiving plane of the solid state imaging device chip 1 with respect to a reference plane 4A of the optical unit 4 depends on the planar accuracy of an attachment plane 7A of the aluminum board 3 and the difference in height between the light receiving plane of the solid state imaging device chip 1 and the attachment plane 7A of the aluminum board 3. It is therefore difficult to accurately position the light receiving plane of the solid state imaging device chip 1.
On the other hand, there is proposed a solid state imaging device which has a vertically positioning piece projecting from a side wall of a package horizontally (Japanese Patent Provisional Publication No. 5-102448). The vertically positioning piece comes into contact with a solid state imaging device attachment part of optical equipment in order to maintain the accurate verticality of the light receiving plane of the solid state imaging device.
To attach the solid state imaging device to the solid state imaging attachment of the optical equipment, the Japanese Patent Provisional Publication No. 5-102448 discloses using adhesives or screws or attaching the solid state imaging device to a printed board and then fixing the printed board to the solid state imaging device attachment part through screws.
In the conventional method of attaching the solid state imaging device, however, the thickness of the aluminum board 3 and the CCD substrate (not illustrated) or the projection of leads 8 increases the thickness along an optical axis as shown in FIG. 11.
If the adhesive is used as mentioned in the Japanese Patent Provisional Publication No. 5-102448, it is troublesome to attach the solid state imaging device to the solid state imaging device attachment part of the optical equipment. If the screws are used, it is necessary to form screw holes must be formed in the vertically positioning piece and therefore the vertically positioning piece must be large. Furthermore, if the solid state imaging device is previously attached to the solid state imaging device attachment part of the optical equipment as stated above, it is very troublesome to solder the leads of the solid state imaging device with terminals of the substrate. Incidentally, if the solid state imaging device is mounted on the substrate and then the substrate is attached to the solid state imaging device attachment part, the positional accuracy is deteriorated as described with reference to FIG. 11.